This paper focuses on strategic information flows between buyers and suppliers within logistics supply chain relationships and on subsequent relationship-specific performance outcomes. Our analysis of dyadic data collected from 91 buyer—supplier logistics relationships finds that buyer and supplier strategic information flows positively impact the relationship-specific performance of both sharing and receiving parties. Specifically, each party gains financially from improved management of assets, reduced costs of operations, and enhanced productivity. Moreover, each benefits operationally from improved planning, control, and flexibility of resources. Buyer dependence on the supplier increases buyer strategic information flows to the supplier. Additionally, buyer IT customization and both buyer and supplier trusting beliefs in the receiving party positively impact strategic information sharing with partners. This study suggests that partnerships for supply chain services engage in cooperative initiatives to generate relational rents and are an alternative to conventional "arms length" transactional exchanges. These partnerships need to be motivated to go beyond the sharing of order-related information (which must occur in transactional exchanges) and to share strategic information (which has the potential for both additional rent generation and risks of misappropriation).